Australian co-author Dr Manuel Cebrian and colleagues show social media and internet penetration is limited by a number of factors including friend networks and response time to messages.

The finding is based on an analysis of the 2009 DARPA Network Challenge and the more recent US State Department's Tag Challenge.

The network challenge involved mobilising teams via social media and the internet to find 10 large red balloons at undisclosed locations across the US, while the tag challenge required competing teams to locate five "thieves" in five different cities in the US and Europe, based only on a mug shot.

The MIT team managed to locate all 10 balloons within nine hours using an incentive scheme to kick start an information and recruitment cascade that resulted in 4400 sign-ups to the team's web site within 48 hours.

Real-world limits

Cebrian says in the current study he and colleagues wanted to test "what the real limits [of the internet and social media] are if everything goes well".

He says they used computer modelling to simulate the balloon challenge a million times using various parameters based on how networks operate and information is spread on the internet.

The team found the balloon challenge "is at the limits of what social media can do today", says Cebrian.

"You can't find 20 balloons and you can't find them in half the time," he says.

Cebrian says this has major implications in the marketing world.

"There are a lot of companies promising things that might not be doable [on the internet]," he says.

Cebrian says in particular claims about the "multiplier effect" of marketing through social media and the internet are misplaced.

It is often promoted, he says, that if you have 10 friends on social media and those 10 friends each have 10 friends, there is the potential to reach 100 people.

However research shows that many friend networks overlap: "So if you and your friends recruit people you get a cluster effect because you and your friends know the same people and therefore the multiplying effect is dampened."

Cebrian says another "choke point" in propagation of events via social media is the response time to a message.

"If you open your twitter account on the train and you see 100 messages, how many of those messages can you really read and then how many will you propagate?"

Terrorism study

Cebrian, who is a member of NICTA's disaster management group, says the study has implications over whether social media can be relied on during disaster management.

The group is currently studying how social media has hindered or helped disaster management.

In a related paper released last week in Nature Scientific Reports, lead author Cebrian also showed how the online recruitment of members to terrorist groups is also limited by social media and the internet.

The study involved observing 10 different extremist forums in a range of countries and languages over a period of four years.

Cebrian concedes the observational capacity of the study was "very limited because of legal constraints" on their involvement with the sites, including not logging in or participating on the forums.

He says, interestingly, the extremist networks operate similarly to the balloon challenge in that there is hierarchical recruitment and a non-centralised organisational structure.

And like the balloon challenge, these sites and networks have "very fragmented and limited ability" to mobilise people.

Cebrian says across the sites they observed all showed grew at similar rates for a similar length of time.

"They all stopped growing at a similar time," says Cebrian. "There has to be an external factor as there is no incentive to self-regulate."

The study highlights these forums operate in a "hostile environment" under constant scrutiny from security agencies that want to shut them down.

Cebrian says their study shows that rather than increasing the number of sites targeted - which can be extremely expensive - it is equally effective to occasionally target large groups.

He says this is because the extremist sites become "more conservative" and "self-regulate" growth to avoid being targeted.

Cebrian stresses however more data is needed in this field to better understand how these groups operate.